There. A major escalation in an already tense conflict. Were live at the pentagon. Those stories plus dangerous weather for people coasttocoast. Acinderella story at the u. S. Open. A change at the u. S. Open. And the twins have arrived. Will we hear from pop star beyonce today . Monday, june 19th, 2017. From nbc news, this is today, with matt lauer and savannah guthrie. Live from studio 1a in rockefeller plaza. And good morning, everybody. Welcome to today. So glad to have you with us on a monday morning. We have willie in for matt this morning. We have a lot happening in your world right now. Thats right. Were going to start with the breaking news out of london. A van slamming into people outside a mosque. The citys mayor calling this a horrific terrorist attack. Weve got complete coverage this morning. Lets start with bill neely at the scene for us. Bill, good morning. What happened . Reporter good morning, savannah. This is britains fourth terror attack in as many months and the th